Gold-Coated Slipring Brush Wire for Low Contact Resistance

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Solution Overview

Problem

Existing slipring and brush assemblies face challenges in manufacturing cost, reliability, and transmission quality, with previous solutions being either expensive or prone to manufacturing difficulties and poor electrical characteristics, especially when brushes are new or their position varies.

Innovation Solution

The use of metal wire or band brushes with selectively coated sections, preferably made of noble metals like gold, silver, or platinum, providing excellent conductivity, mechanical properties, and low contact resistance, coated using electroplating, PVD, or CVD methods to ensure long-lasting and reliable contact with a slipring module.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the brush is made of solid gold wire spring, then excellent electrical characteristics and reliability are achieved, but manufacturing cost increases significantly and the structure becomes more complex

Engineering Contradiction:
Improveelectrical characteristicsVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The brush wire is manufactured with a gold coating applied only to specific sections (contact regions) rather than the entire wire. This selective coating approach uses electroplating or PVD/CVD methods to deposit gold only where needed for electrical contact, significantly reducing gold consumption and manufacturing cost while maintaining excellent electrical characteristics at the contact interface.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The brush wire consists of a composite structure combining a base metal (such as copper or copper alloy) with a gold coating layer. This composite material approach leverages the high electrical conductivity of both the base metal and gold, providing excellent electrical characteristics while using far less gold than a solid gold brush would require, thereby reducing manufacturing cost.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a gold sleeve is applied to the end of the wire spring, then contact resistance is reduced, but manufacturing difficulty increases and the sleeve may be pulled off resulting in complete loss of transmission characteristics

Engineering Contradiction:
Improvecontact resistanceVSAvoidmanufacturing difficulty
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The gold coating is applied to the brush wire during the manufacturing process itself, before the brush is assembled into the final device. This preliminary coating ensures that the gold layer is already bonded to the wire and cannot be pulled off during operation. The coating is applied to the specific contact regions that will establish sliding contact with the slipring, ensuring low contact resistance from the start without requiring separate assembly steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The gold coating acts as an intermediary layer between the base metal wire and the contact interface with the slipring. This intermediate gold layer provides excellent electrical conductivity and low contact resistance while being metallurgically bonded to the base metal, preventing delamination issues that would occur with mechanically attached sleeves.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach simplifies manufacturing, reduces costs, enhances reliability, and maintains high transmission quality by ensuring low wear rates and extended lifespan of the contact system, with a friction coefficient optimized for both lubricated and non-lubricated systems.

Implementation Method 1

coated using electroplating, PVD, or CVD methods

Methodology Applied
Scientific EffectElectroplating: Electroplating

Implementation Method 2

coated using electroplating, PVD, or CVD methods

Methodology Applied
Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 3

coated using electroplating, PVD, or CVD methods

Methodology Applied
Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Data Source

PatentEP2696450B1Low cost brush with gold coated wire
Publication Date: 2020.09.30 SCHLEIFRING GMBH
  • EP2696450B1 patent drawingFigure 1~4
  • EP2696450B1 patent drawingFigure 5~7
  • EP2696450B1 patent drawingFigure 8~10

AI summary

A slipring brush comprises a body of a metal wire or metal band having a contact area for contacting a slipring module. The contact area is selectively coated by a contact material like gold or silver or an alloy thereof. The body preferably comprises Copper, Nickel or Iron or an alloy thereof. Coating may be done by electroplating, physical vapor deposition (PVD) or chemical vapor deposition (CVD).